[linux.git] / fs / jffs2 / read.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 *
 * Created by David Woodhouse <[email protected]>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/crc32.h>
#include <linux/pagemap.h>
#include <linux/mtd/mtd.h>
#include <linux/compiler.h>
#include "nodelist.h"
#include "compr.h"

int jffs2_read_dnode(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
		     struct jffs2_full_dnode *fd, unsigned char *buf,
		     int ofs, int len)
{
	struct jffs2_raw_inode *ri;
	size_t readlen;
	uint32_t crc;
	unsigned char *decomprbuf = NULL;
	unsigned char *readbuf = NULL;
	int ret = 0;

	ri = jffs2_alloc_raw_inode();
	if (!ri)
		return -ENOMEM;

	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(*ri), &readlen, (char *)ri);
	if (ret) {
		jffs2_free_raw_inode(ri);
		printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
		return ret;
	}
	if (readlen != sizeof(*ri)) {
		jffs2_free_raw_inode(ri);
		printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
		       ref_offset(fd->raw), sizeof(*ri), readlen);
		return -EIO;
	}
	crc = crc32(0, ri, sizeof(*ri)-8);

	D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
		  ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
		  crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
		  je32_to_cpu(ri->offset), buf));
	if (crc != je32_to_cpu(ri->node_crc)) {
		printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
		       je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
		ret = -EIO;
		goto out_ri;
	}
	/* There was a bug where we wrote hole nodes out with csize/dsize
	   swapped. Deal with it */
	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
	    je32_to_cpu(ri->csize)) {
		ri->dsize = ri->csize;
		ri->csize = cpu_to_je32(0);
	}

	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
		printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
		       len, ofs, je32_to_cpu(ri->dsize));
		ret = -EINVAL;
		goto out_ri;
	});


	if (ri->compr == JFFS2_COMPR_ZERO) {
		memset(buf, 0, len);
		goto out_ri;
	}

	/* Cases:
	   Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
	   Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
	   Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
	   Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
	*/
	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
		readbuf = buf;
	} else {
		readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
		if (!readbuf) {
			ret = -ENOMEM;
			goto out_ri;
		}
	}
	if (ri->compr != JFFS2_COMPR_NONE) {
		if (len < je32_to_cpu(ri->dsize)) {
			decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
			if (!decomprbuf) {
				ret = -ENOMEM;
				goto out_readbuf;
			}
		} else {
			decomprbuf = buf;
		}
	} else {
		decomprbuf = readbuf;
	}

	D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
		  readbuf));
	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
			       je32_to_cpu(ri->csize), &readlen, readbuf);

	if (!ret && readlen != je32_to_cpu(ri->csize))
		ret = -EIO;
	if (ret)
		goto out_decomprbuf;

	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
	if (crc != je32_to_cpu(ri->data_crc)) {
		printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
		       je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
		ret = -EIO;
		goto out_decomprbuf;
	}
	D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
	if (ri->compr != JFFS2_COMPR_NONE) {
		D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
			  je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
		ret = jffs2_decompress(c, f, ri->compr | (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
		if (ret) {
			printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
			goto out_decomprbuf;
		}
	}

	if (len < je32_to_cpu(ri->dsize)) {
		memcpy(buf, decomprbuf+ofs, len);
	}
 out_decomprbuf:
	if(decomprbuf != buf && decomprbuf != readbuf)
		kfree(decomprbuf);
 out_readbuf:
	if(readbuf != buf)
		kfree(readbuf);
 out_ri:
	jffs2_free_raw_inode(ri);

	return ret;
}

int jffs2_read_inode_range(struct jffs2_sb_info *c, struct jffs2_inode_info *f,
			   unsigned char *buf, uint32_t offset, uint32_t len)
{
	uint32_t end = offset + len;
	struct jffs2_node_frag *frag;
	int ret;

	D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
		  f->inocache->ino, offset, offset+len));

	frag = jffs2_lookup_node_frag(&f->fragtree, offset);

	/* XXX FIXME: Where a single physical node actually shows up in two
	   frags, we read it twice. Don't do that. */
	/* Now we're pointing at the first frag which overlaps our page
	 * (or perhaps is before it, if we've been asked to read off the
	 * end of the file). */
	while(offset < end) {
		D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
		if (unlikely(!frag || frag->ofs > offset ||
			     frag->ofs + frag->size <= offset)) {
			uint32_t holesize = end - offset;
			if (frag && frag->ofs > offset) {
				D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
				holesize = min(holesize, frag->ofs - offset);
			}
			D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
			memset(buf, 0, holesize);
			buf += holesize;
			offset += holesize;
			continue;
		} else if (unlikely(!frag->node)) {
			uint32_t holeend = min(end, frag->ofs + frag->size);
			D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
			memset(buf, 0, holeend - offset);
			buf += holeend - offset;
			offset = holeend;
			frag = frag_next(frag);
			continue;
		} else {
			uint32_t readlen;
			uint32_t fragofs; /* offset within the frag to start reading */

			fragofs = offset - frag->ofs;
			readlen = min(frag->size - fragofs, end - offset);
			D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
				  frag->ofs+fragofs, frag->ofs+fragofs+readlen,
				  ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
			ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
			D2(printk(KERN_DEBUG "node read done\n"));
			if (ret) {
				D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
				memset(buf, 0, readlen);
				return ret;
			}
			buf += readlen;
			offset += readlen;
			frag = frag_next(frag);
			D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
		}
	}
	return 0;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* JFFS2 -- Journalling Flash File System, Version 2.
	3	*
c00c310e	4	* Copyright © 2001-2007 Red Hat, Inc.
1da177e4 LT	5	*
	6	* Created by David Woodhouse <[email protected]>
	7	*
	8	* For licensing information, see the file 'LICENCE' in this directory.
	9	*
1da177e4 LT	10	*/
	11
	12	#include <linux/kernel.h>
	13	#include <linux/slab.h>
	14	#include <linux/crc32.h>
	15	#include <linux/pagemap.h>
	16	#include <linux/mtd/mtd.h>
	17	#include <linux/compiler.h>
	18	#include "nodelist.h"
	19	#include "compr.h"
	20
	21	int jffs2_read_dnode(struct jffs2_sb_info c, struct jffs2_inode_info f,
	22	struct jffs2_full_dnode fd, unsigned char buf,
	23	int ofs, int len)
	24	{
	25	struct jffs2_raw_inode *ri;
	26	size_t readlen;
	27	uint32_t crc;
	28	unsigned char *decomprbuf = NULL;
	29	unsigned char *readbuf = NULL;
	30	int ret = 0;
	31
	32	ri = jffs2_alloc_raw_inode();
	33	if (!ri)
	34	return -ENOMEM;
	35
	36	ret = jffs2_flash_read(c, ref_offset(fd->raw), sizeof(ri), &readlen, (char )ri);
	37	if (ret) {
	38	jffs2_free_raw_inode(ri);
	39	printk(KERN_WARNING "Error reading node from 0x%08x: %d\n", ref_offset(fd->raw), ret);
	40	return ret;
	41	}
	42	if (readlen != sizeof(*ri)) {
	43	jffs2_free_raw_inode(ri);
182ec4ee	44	printk(KERN_WARNING "Short read from 0x%08x: wanted 0x%zx bytes, got 0x%zx\n",
1da177e4 LT	45	ref_offset(fd->raw), sizeof(*ri), readlen);
	46	return -EIO;
	47	}
	48	crc = crc32(0, ri, sizeof(*ri)-8);
	49
	50	D1(printk(KERN_DEBUG "Node read from %08x: node_crc %08x, calculated CRC %08x. dsize %x, csize %x, offset %x, buf %p\n",
	51	ref_offset(fd->raw), je32_to_cpu(ri->node_crc),
	52	crc, je32_to_cpu(ri->dsize), je32_to_cpu(ri->csize),
	53	je32_to_cpu(ri->offset), buf));
	54	if (crc != je32_to_cpu(ri->node_crc)) {
	55	printk(KERN_WARNING "Node CRC %08x != calculated CRC %08x for node at %08x\n",
	56	je32_to_cpu(ri->node_crc), crc, ref_offset(fd->raw));
	57	ret = -EIO;
	58	goto out_ri;
	59	}
	60	/* There was a bug where we wrote hole nodes out with csize/dsize
	61	swapped. Deal with it */
182ec4ee	62	if (ri->compr == JFFS2_COMPR_ZERO && !je32_to_cpu(ri->dsize) &&
1da177e4 LT	63	je32_to_cpu(ri->csize)) {
	64	ri->dsize = ri->csize;
	65	ri->csize = cpu_to_je32(0);
	66	}
	67
	68	D1(if(ofs + len > je32_to_cpu(ri->dsize)) {
	69	printk(KERN_WARNING "jffs2_read_dnode() asked for %d bytes at %d from %d-byte node\n",
	70	len, ofs, je32_to_cpu(ri->dsize));
	71	ret = -EINVAL;
	72	goto out_ri;
	73	});
	74
182ec4ee	75
1da177e4 LT	76	if (ri->compr == JFFS2_COMPR_ZERO) {
	77	memset(buf, 0, len);
	78	goto out_ri;
	79	}
	80
	81	/* Cases:
	82	Reading whole node and it's uncompressed - read directly to buffer provided, check CRC.
182ec4ee TG	83	Reading whole node and it's compressed - read into comprbuf, check CRC and decompress to buffer provided
182ec4ee TG	84	Reading partial node and it's uncompressed - read into readbuf, check CRC, and copy
1da177e4 LT	85	Reading partial node and it's compressed - read into readbuf, check checksum, decompress to decomprbuf and copy
	86	*/
	87	if (ri->compr == JFFS2_COMPR_NONE && len == je32_to_cpu(ri->dsize)) {
	88	readbuf = buf;
	89	} else {
	90	readbuf = kmalloc(je32_to_cpu(ri->csize), GFP_KERNEL);
	91	if (!readbuf) {
	92	ret = -ENOMEM;
	93	goto out_ri;
	94	}
	95	}
	96	if (ri->compr != JFFS2_COMPR_NONE) {
	97	if (len < je32_to_cpu(ri->dsize)) {
	98	decomprbuf = kmalloc(je32_to_cpu(ri->dsize), GFP_KERNEL);
	99	if (!decomprbuf) {
	100	ret = -ENOMEM;
	101	goto out_readbuf;
	102	}
	103	} else {
	104	decomprbuf = buf;
	105	}
	106	} else {
	107	decomprbuf = readbuf;
	108	}
	109
	110	D2(printk(KERN_DEBUG "Read %d bytes to %p\n", je32_to_cpu(ri->csize),
	111	readbuf));
	112	ret = jffs2_flash_read(c, (ref_offset(fd->raw)) + sizeof(*ri),
	113	je32_to_cpu(ri->csize), &readlen, readbuf);
	114
	115	if (!ret && readlen != je32_to_cpu(ri->csize))
	116	ret = -EIO;
	117	if (ret)
	118	goto out_decomprbuf;
	119
	120	crc = crc32(0, readbuf, je32_to_cpu(ri->csize));
	121	if (crc != je32_to_cpu(ri->data_crc)) {
	122	printk(KERN_WARNING "Data CRC %08x != calculated CRC %08x for node at %08x\n",
	123	je32_to_cpu(ri->data_crc), crc, ref_offset(fd->raw));
	124	ret = -EIO;
	125	goto out_decomprbuf;
	126	}
	127	D2(printk(KERN_DEBUG "Data CRC matches calculated CRC %08x\n", crc));
	128	if (ri->compr != JFFS2_COMPR_NONE) {
	129	D2(printk(KERN_DEBUG "Decompress %d bytes from %p to %d bytes at %p\n",
182ec4ee	130	je32_to_cpu(ri->csize), readbuf, je32_to_cpu(ri->dsize), decomprbuf));
1da177e4 LT	131	ret = jffs2_decompress(c, f, ri->compr \| (ri->usercompr << 8), readbuf, decomprbuf, je32_to_cpu(ri->csize), je32_to_cpu(ri->dsize));
	132	if (ret) {
	133	printk(KERN_WARNING "Error: jffs2_decompress returned %d\n", ret);
	134	goto out_decomprbuf;
	135	}
	136	}
	137
	138	if (len < je32_to_cpu(ri->dsize)) {
	139	memcpy(buf, decomprbuf+ofs, len);
	140	}
	141	out_decomprbuf:
	142	if(decomprbuf != buf && decomprbuf != readbuf)
	143	kfree(decomprbuf);
	144	out_readbuf:
	145	if(readbuf != buf)
	146	kfree(readbuf);
	147	out_ri:
	148	jffs2_free_raw_inode(ri);
	149
	150	return ret;
	151	}
	152
	153	int jffs2_read_inode_range(struct jffs2_sb_info c, struct jffs2_inode_info f,
	154	unsigned char *buf, uint32_t offset, uint32_t len)
	155	{
	156	uint32_t end = offset + len;
	157	struct jffs2_node_frag *frag;
	158	int ret;
	159
	160	D1(printk(KERN_DEBUG "jffs2_read_inode_range: ino #%u, range 0x%08x-0x%08x\n",
	161	f->inocache->ino, offset, offset+len));
	162
	163	frag = jffs2_lookup_node_frag(&f->fragtree, offset);
	164
	165	/* XXX FIXME: Where a single physical node actually shows up in two
	166	frags, we read it twice. Don't do that. */
199bc9ff DW	167	/* Now we're pointing at the first frag which overlaps our page
	168	* (or perhaps is before it, if we've been asked to read off the
	169	* end of the file). */
1da177e4 LT	170	while(offset < end) {
1da177e4 LT	171	D2(printk(KERN_DEBUG "jffs2_read_inode_range: offset %d, end %d\n", offset, end));
199bc9ff DW	172	if (unlikely(!frag \|\| frag->ofs > offset \|\|
199bc9ff DW	173	frag->ofs + frag->size <= offset)) {
1da177e4	174	uint32_t holesize = end - offset;
199bc9ff	175	if (frag && frag->ofs > offset) {
1da177e4 LT	176	D1(printk(KERN_NOTICE "Eep. Hole in ino #%u fraglist. frag->ofs = 0x%08x, offset = 0x%08x\n", f->inocache->ino, frag->ofs, offset));
1da177e4 LT	177	holesize = min(holesize, frag->ofs - offset);
1da177e4 LT	178	}
	179	D1(printk(KERN_DEBUG "Filling non-frag hole from %d-%d\n", offset, offset+holesize));
	180	memset(buf, 0, holesize);
	181	buf += holesize;
	182	offset += holesize;
	183	continue;
	184	} else if (unlikely(!frag->node)) {
	185	uint32_t holeend = min(end, frag->ofs + frag->size);
	186	D1(printk(KERN_DEBUG "Filling frag hole from %d-%d (frag 0x%x 0x%x)\n", offset, holeend, frag->ofs, frag->ofs + frag->size));
	187	memset(buf, 0, holeend - offset);
	188	buf += holeend - offset;
	189	offset = holeend;
	190	frag = frag_next(frag);
	191	continue;
	192	} else {
	193	uint32_t readlen;
	194	uint32_t fragofs; /* offset within the frag to start reading */
182ec4ee	195
1da177e4 LT	196	fragofs = offset - frag->ofs;
	197	readlen = min(frag->size - fragofs, end - offset);
	198	D1(printk(KERN_DEBUG "Reading %d-%d from node at 0x%08x (%d)\n",
	199	frag->ofs+fragofs, frag->ofs+fragofs+readlen,
	200	ref_offset(frag->node->raw), ref_flags(frag->node->raw)));
	201	ret = jffs2_read_dnode(c, f, frag->node, buf, fragofs + frag->ofs - frag->node->ofs, readlen);
	202	D2(printk(KERN_DEBUG "node read done\n"));
	203	if (ret) {
	204	D1(printk(KERN_DEBUG"jffs2_read_inode_range error %d\n",ret));
	205	memset(buf, 0, readlen);
	206	return ret;
	207	}
	208	buf += readlen;
	209	offset += readlen;
	210	frag = frag_next(frag);
	211	D2(printk(KERN_DEBUG "node read was OK. Looping\n"));
	212	}
	213	}
	214	return 0;
	215	}
	216